Disaster !! Bad Collapse Handling

I'm not sure about the right brake being the root cause of the collapse. There was an obvious gust of wind, followed by a lull. The wing pitches up and climbs during the gust, then pitches forward to try to gain flying speed during the lull, unloading the leading edge of the wing and making it susceptable to collapse. The pilot should have applied brakes to prevent the wing from surging forward so radically. IMO, of course.

I agree with your analysis entirely. It does seem that the pilot was not actively flying before the collapse and really needed to concentrate fully to gain height and increase the margin of safety.

I am always amazed at how badly things can go seriously wrong in such a very short space of time.

If you have a 50% collapse there is no riser lift on that side and you will be suspended on the flying side by default but your harness becomes lopsided, you cannot weight shift efectively until you recover to a degree. So I don't think he weight shifted wrong, he just lost riser support there. With hindsight more aggressive toggle input to keep it straight may have saved him, experts caution against this and they're generally right but when you're this low it's hobson's choice.

To clarify, SOME toggle input is appropriate, but overcontrol and overreaction is a big contributor to making collapses worse. In this case there wasn't much of any reaction. Either to prevent the collapse (his hands are gripping the risers), or to keep it flying straight with toggles. Even some outside break would have reduced his loss of altitude during the induced turn.